[R-sig-ME] repeated measures: levels of grouping factor must be less than number of obs
bpederse at gmail.com
Mon Apr 18 17:49:38 CEST 2011
On Mon, Apr 18, 2011 at 9:44 AM, Andrew Miles <rstuff.miles at gmail.com> wrote:
> Just to clarify, when you say repeated measures do you mean that you have
> data from multiple individuals from the same family? Or do you mean that
> you have data on the same individuals across multiple time points (ex. data
> from person one on Monday, and Tuesday, and Wednesday, etc.)? The latter is
> what is more traditionally referred to as a repeated measures study; the
> first is simply clustering in the data.
yes, I was unclear.
I mean the former: data from multiple individuals in the same family.
*In addition*, each proband subject
may be represented twice--once for each of his/her siblings.
> If the first (i.e. the clustered data), the model you have specified is
> sufficient. Specifically, it will estimate a variance component that will
> tell you how much variation there is in y between family groups.
> Hope that helps.
> Andrew Miles
> On Apr 18, 2011, at 11:33 AM, Brent Pedersen wrote:
>> hi, I posted this to the main R mailing list a while back and people
>> directed me to
>> the lme4 package and this mailing list so I thought I might get more
>> help here...
>> We have some data, a subset of which is pasted at the end of this message.
>> I am trying to understand how to do repeated measures as our study
>> design consists of a subject (proband) and 1 or 2 siblings.
>> Thus far, our model looks like this--with family_id indicating a
>> sibling relationship:
>>> model = lmer(y ~ concordant + age.proband + age.other + sex.proband +
>>> sex.proband + sex.other + (1| family_id), data=df2)
>> is the above formulation sufficient to capture the repeated measures by
>> Next, when I do this with lme4a, I get an error:
>> Error in lmer(y ~ concordant + age.proband + age.other + sex.proband + :
>> number of levels of each grouping factor must be less than number of obs
>> I have seen this thread:
>> but the change does not appear to be included in the latest lme4a
>> package from Rforge, is there another repo where this has been
>> incorporated? or is this an error on my part?
>> concordant family_id external_ref.proband external_ref.other
>> sex.proband sex.other age.proband age.other y(fake)
>> T 58 80015550 80015543 M F 15 19 1
>> F 58 80015550 80016946 M F 15 8 2
>> T 54 80015499 80015338 F F 5 7 3
>> F 54 80015499 80013112 F M 5 13 4
>> F 22 80012269 80012252 F F 12 10 5
>> F 22 80012269 80018691 F M 12 8 5
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